It is often desirable, and sometimes necessary, to know the location or position of a wireless device in a network. The terms “location” and “position” are synonymous and are used interchangeably herein. For example, a user may utilize the wireless device to browse through a website and may click on location sensitive content. A web server may then query the network for the position of the wireless device. The network may initiate position processing with the wireless device in order to ascertain the position of the wireless device. The network may then return a position estimate for the wireless device to the web server, which may use this position estimate to provide appropriate content to the user. There are many other scenarios in which knowledge of the position of the wireless device is useful or necessary.
A message flow (which may also be called a call flow or a procedure) is typically executed in order to obtain a position estimate for the wireless device and to send this position estimate to a client entity, e.g., the web server. Various messages are typically exchanged between one or more network entities, the wireless device, and the client entity for the message flow. These messages ensure that each entity is provided with pertinent information, or can obtain this information from another entity, in order to carry out positioning for the wireless device and/or to deliver the position estimate to the client entity. However, these messages add to the traffic among the various network entities. The additional traffic may be especially great for location services in which a position estimate for the wireless device is periodically provided to the client entity. The messages may also extend the response time for sending the position estimate to the client entity. Furthermore, different types of location service (e.g. provision of a single location estimate, provision of a location estimate at fixed periodic intervals, provision of a location estimate whenever some trigger condition is encountered) may be associated with different types of message flow which may add cost and complexity to the support of multiple types of location service.
One commonly used protocol for location based services is known as Secure User Plane Location (SUPL) 2.0. In the SUPL 2.0 protocol, assistance and positioning data is sent over the user's traffic channel using a secure connection between the SUPL enabled Terminal (SET) and the SUPL Location Platform (SLP) on the network side. While SUPL 2.0 is a secure means to efficiently provide location based services, improvements are desirable.